Reactive compatibilization of recycled low density polyethylene/butadiene rubber blends during dynamic vulcanization

For reactive compatibilization of the recycled LDPE with butadiene rubber (BR) an equal quantity of few couples of reactive polyethylene copolymer/reactive polybutadiene (1/1) were introduced into the corresponding phases before the dynamic vulcanization. The LDPE/BR thermoplastic dynamic vulcanizates (TDVs) produced using the poly(ethylene-co-acrylic acid), PE-AA/polybutadiene terminated with isocyanate groups, PB-NCO compatibilizing couple with different ratio of functional groups have demonstrated the best mechanical properties and have been characterized by X-Ray analysis and DMTA measurements. For all of systems studied the increasing components compatibility due to the formation of the essential interface layer have been observed. The PB-NCO modifier participates in two processes: it is co-vulcanised with BR in rubber phase and reacts in the interface with the PE-AA dissolved in LDPE. The amorphous phase of LDPE is dissolved by rubber phase, i.e. the morphology with dual phase continuity is formed that provides an improvement of mechanical characteristics of material obtained. The best combination of mechanical characteristics was obtained for LDPE(PE-AA)/BR(PB-NCO), PB-NCO=7.5 wt.% per PB, COOH/NCO=1/1. The tensile strength and an elongation at break for these blends were 3.9 MPa and 353% and for the basic non-compatibilized blend 3.2 MPa and 217%, relatively.